Ozone occurs naturally in the stratosphere where it forms a protective layer that shields us from harmful ultraviolet rays. This is called "good" ozone. Human activity has depleted this ozone layer and caused "holes," but due to a reduction in the use of certain chemicals, it is predicted that the ozone layer could recover. Ground-level ozone is called "bad" ozone and is the main ingredient in smog. It is also the primary pollutant of concern in southeast Florida. When emissions from motor vehicles, lawn maintenance equipment, power plants and gas stations react with the sun, they form ozone. Warm temperatures and low wind speeds during the summer months make summer the ozone season!

Ozone in the Southeast Florida Airshed

Ozone does not recognize county boundaries. Instead, it drifts within air masses throughout our region. The U.S. Environmental Protection Agency (EPA) has established a national health standard for ozone and determined that Broward, Miami-Dade and Palm Beach counties are considered the southeast Florida airshed.

Broward County

In 1979, Broward County and the southeast Florida airshed encountered high ozone levels, and we were considered a non-attainment area for ozone. We exceeded the levels for ozone that were based on national health standards established by the EPA called the National Ambient Air Quality Standard (NAAQS).

In 1990 the Clean Air Act Amendments (CAA) required automobile manufacturers to produce cleaner cars that run on cleaner fuels, and implemented programs to control ozone forming emissions. An example is the vapor recovery devices at gas pumps. Due to measures such as these and local efforts, the S.E. Florida airshed was reclassified in 1995 as attainment for ozone!

Ozone and Your Health

When inhaled, ozone can cause permanent lung damage. Ozone can trigger a variety of health problems including chest pains, coughing, nausea, throat and nose irritation, and congestion. Ozone pollution reduces the capacity of the lungs and can increase the effects of respiratory illness, heart disease and asthma. Young children, older adults, and those with preexisting respiratory conditions and heart disease are most at risk.

Air Quality Index

The Air Quality Index (AQI) is an index for reporting daily air quality. It tells you how clean or polluted your air is, and what associated health effects might be a concern for you. Think of the AQI as a yardstick that runs from 0 to 500; the higher the AQI value, the greater the health concern. When the AQI level reaches above 100, air quality is considered to be unhealthy.

Daily Air Quality Index forecast

To find out more about ozone levels in your area, go to www.airnow.gov. You can also sign up to receive e-mail notifications about the air quality in Broward County by visiting EPA's Enviroflash web site at https://enviroflash.epa.gov.